Jackie says the fame and fortune was a far cry from the two-bedroom house his 12-person family shared in Gary, Indiana. "When I was there, I thought it was a big mansion," he says. "Then I went back and I go: 'I can't believe I lived in this house. My garage is bigger than that house.'"

Jackie says the family wouldn't be where they are now without his father, Joe. "I'm proud that my father did raise us the right way. But when I was growing up, I thought he was kind of hard at the time," he says. "It was a tough neighborhood. He had to be stern. I can look back on it and say he did such a wonderful job."

Growing up, Jackie says he also felt extra responsibility as the oldest boy to make sure his brothers were safe. "I was so protective over my brothers," he says.

Still, Jackie says he was the most reserved. "I was always quiet," he says. "Michael was a quiet person too."

Jackie says Michael was also the biggest prankster—and the most balanced when it came to handling fame. "When he hit the stage, he was a different person," he says. "I knew that from the very beginning that he had the magic."